rust-lang · jschwe · Feb 2, 2025
diff --git a/bindgen-tests/tests/expectations/tests/anon_union.rs b/bindgen-tests/tests/expectations/tests/anon_union.rs
diff --git a/bindgen-tests/tests/expectations/tests/forward-declaration-autoptr.rs b/bindgen-tests/tests/expectations/tests/forward-declaration-autoptr.rs
diff --git a/bindgen-tests/tests/expectations/tests/forward_declared_complex_types.rs b/bindgen-tests/tests/expectations/tests/forward_declared_complex_types.rs
diff --git a/bindgen-tests/tests/expectations/tests/forward_declared_opaque.rs b/bindgen-tests/tests/expectations/tests/forward_declared_opaque.rs
diff --git a/bindgen-tests/tests/expectations/tests/func_return_must_use.rs b/bindgen-tests/tests/expectations/tests/func_return_must_use.rs
diff --git a/bindgen-tests/tests/expectations/tests/issue-1443.rs b/bindgen-tests/tests/expectations/tests/issue-1443.rs
diff --git a/bindgen-tests/tests/expectations/tests/issue-654-struct-fn-collision.rs b/bindgen-tests/tests/expectations/tests/issue-654-struct-fn-collision.rs
diff --git a/bindgen-tests/tests/expectations/tests/issue-710-must-use-type.rs b/bindgen-tests/tests/expectations/tests/issue-710-must-use-type.rs
diff --git a/bindgen-tests/tests/expectations/tests/issue-801-opaque-sloppiness.rs b/bindgen-tests/tests/expectations/tests/issue-801-opaque-sloppiness.rs
diff --git a/bindgen-tests/tests/expectations/tests/layout_array.rs b/bindgen-tests/tests/expectations/tests/layout_array.rs
diff --git a/bindgen-tests/tests/expectations/tests/operator.rs b/bindgen-tests/tests/expectations/tests/operator.rs
diff --git a/bindgen-tests/tests/expectations/tests/parm-union.rs b/bindgen-tests/tests/expectations/tests/parm-union.rs
diff --git a/bindgen-tests/tests/expectations/tests/same_struct_name_in_different_namespaces.rs b/bindgen-tests/tests/expectations/tests/same_struct_name_in_different_namespaces.rs
diff --git a/bindgen-tests/tests/expectations/tests/template.rs b/bindgen-tests/tests/expectations/tests/template.rs
diff --git a/bindgen-tests/tests/expectations/tests/typedef-pointer-overlap.rs b/bindgen-tests/tests/expectations/tests/typedef-pointer-overlap.rs
diff --git a/bindgen-tests/tests/expectations/tests/wrap-static-fns.rs b/bindgen-tests/tests/expectations/tests/wrap-static-fns.rs
diff --git a/bindgen-tests/tests/expectations/tests/wrap_unsafe_ops_anon_union.rs b/bindgen-tests/tests/expectations/tests/wrap_unsafe_ops_anon_union.rs
diff --git a/bindgen-tests/tests/headers/func_return_must_use.h b/bindgen-tests/tests/headers/func_return_must_use.h
@@ -4,7 +4,9 @@ typedef int MustUseInt;
 
 MustUseInt return_int();
 
-struct MustUseStruct;
+struct MustUseStruct {
+    int a;
+};
 
 struct MustUseStruct return_struct();
 
@@ -20,11 +22,15 @@ int return_plain_int();
 /**
  * <div rustbindgen mustusetype></div>
  */
-struct AnnotatedStruct {};
+struct AnnotatedStruct {
+    int a;
+};
 
 struct AnnotatedStruct return_annotated_struct();
 
-struct PlainStruct {};
+struct PlainStruct {
+    int a;
+};
 
 /**
  * <div rustbindgen mustusetype></div>

diff --git a/bindgen-tests/tests/headers/issue-1238-fwd-no-copy.h b/bindgen-tests/tests/headers/issue-1238-fwd-no-copy.h
@@ -1,3 +1,2 @@
-// bindgen-flags: --no-copy MyType
 
 typedef struct MyType MyTypeT;
diff --git a/bindgen/codegen/mod.rs b/bindgen/codegen/mod.rs
@@ -2444,7 +2444,17 @@ impl CodeGenerator for CompInfo {
             }
         }
 
-        let derivable_traits = derives_of_item(item, ctx, packed);
+        let derivable_traits = if self.is_forward_declaration() {
+            // The only trait we can derive for forward declared types is `Debug`,
+            // since we don't know anything about the layout or type.
+            let mut derivable_traits = DerivableTraits::empty();
+            if !item.annotations().disallow_debug() {
+                derivable_traits |= DerivableTraits::DEBUG;
+            };
+            derivable_traits
+        } else {
+            derives_of_item(item, ctx, packed)
+        };
         if !derivable_traits.contains(DerivableTraits::DEBUG) {
             needs_debug_impl = ctx.options().derive_debug &&
                 ctx.options().impl_debug &&

diff --git a/bindgen/ir/analysis/derive.rs b/bindgen/ir/analysis/derive.rs
@@ -510,7 +510,7 @@ impl DeriveTrait {
     }
 
     fn can_derive_compound_forward_decl(self) -> bool {
-        matches!(self, DeriveTrait::Copy | DeriveTrait::Debug)
+        matches!(self, DeriveTrait::Debug)
     }
 
     fn can_derive_incomplete_array(self) -> bool {
Original file line number	Diff line number	Diff line change
		@@ -1,3 +1,2 @@
		// bindgen-flags: --no-copy MyType

		typedef struct MyType MyTypeT;